1) Field of the Invention
The invention herein relates to an improved top die raising and lowering guide mechanism for punching, pressing, and shearing machines.
2) Description of the Prior Art
In conventional punching, pressing, and shearing machines, the top die is typically raised and lowered, as indicated in FIG. 1, by a hydraulic system (hydraulic pump, not shown in the drawing) driving a single hydraulic cylinder 1 or a cam (not shown in the drawing) rotated by a motor (not shown in the drawing), with the said top die 2 pre-mounted to a guide block 3, and the guide block 3 is raised and lowered via an attachment block 4 driven by the piston rod 11 of the hydraulic cylinder 1 or a rotating cam; wherein, when the top die 2 on the said guide block 3 is raised or lowered by the hydraulic cylinder 1 piston rod 11, the piston rod 11 tends to twist since it is a freely rotating component or, in the case of the eccentric movement of a rotating cam, flexion occurs; as such, the machine A is normally equipped with a guide track 2 installed on two sides in which the two ends of guide block 3 slide and thereby accurately ascend and descend in a straight line.
The said guide block 3 and guide tracks 5 are produced in numerous arrangements and, as indicated in FIG. 2, the guide track 5 can consist of the three guide elements 51, 52, and 53 formed into a U-shaped fixture and, furthermore, the said left and right fixtures are respectively fastened to the two sides of the machine A, with the two projecting ends of the guide block 3 then each fitted into the two guide tracks 5 so they can slide in contact with them or, as indicated in FIG. 3, the left and right guide tracks 5 can be formed as a negative V-shaped profile and fastened to the two sides of the machine A and the guide block 3 ends machined to a positive V-shaped profile capable of sliding in them. Or, as indicated in FIG. 4, when utilized on a larger model machine, the left and right guide tracks 5 are formed from two guide elements 51 and each pair of guide elements 51 is respectively fastened to the two sides of the machine A, a locating block 31 is situated on each of the two sides of the guide block 3 ends, and a sliding block 32 is disposed in between the locating blocks 31 and the guide elements 51.
While utilizing the said guide block 2 and two guide tracks 5 in a sliding arrangement to raise and lower the top die 2 in a straight line is of practical value and provides functional performance and, furthermore, is the most commonly used type of guide mechanism on punching, pressing, and shearing machines, following long-term usage, the industry and users have become aware that the following shortcomings await improvement:
1. Since the installation of the said guide block 3 must take into consideration differences in machine size, especially in the case of larger units, and furthermore, the two ends must be precision machined and ground to fabricate smooth and even sliding surfaces, therefore, construction, finishing, and assembly is often troublesome, inconvenient, and more expensive in terms of production cost.
2. Since the said guide tracks 5 must provide for the raising and lowering of the guide blocks 3 in a straight line without flexion and twisting, precision construction and assembly is required to achieve the sliding of the guide block 3 that involves the shortcomings of difficult and time-consuming machining, and especially the necessity of adjusting them to the proper verticality on the machine A, which is troublesome, inconvenient, time-consuming, and difficult.
3. Since lubrication must be applied periodically between the said guide block 3 and guide tracks 5 to reduce friction, therefore, in addition to the general inconvenience and troublesome nature, the lubrication attracts dust and the accumulation often gives rise to thick build-ups of sludge, resulting in an untidy machine.
4. Since the said guide block 3 and guide tracks 5 are installed in an exposed state, therefore, they readily attract dust and debris that increases friction, with the wear after long-term operation causing drift and flexion during raising and lowering which reduces the punching, pressing, and shearing precision of the top die 2.
5. Given the said situations, to maintain the functional precision of the top die 2, the said guide block 3 and guide tracks 5 must be machined or replaced following a certain period of utilization, which not only involves disassembly, assembly, and re-machining, but is extremely troublesome and inconvenient and, furthermore, the said replacement operation is wasteful and uneconomical.
6. When the hydraulic system drives a single hydraulic cylinder and, furthermore, is utilized on a larger model machine, especially with regard to considerations of precision, the greater weight of the single hydraulic cylinder makes it more difficult to produce and, furthermore, troublesome (larger dimensioned hydraulic cylinder are more challenging to produce) and this results in uneconomical production overhead and, furthermore, the overall cost is higher when fabricating guide blocks 3 and guide tracks 5 capable of raising and lowering the top die 2.
In summation of the foregoing section, conventional guide blocks and guide tracks serving as mechanisms that guide the raising and lowering of the top die are of an impractical design having obvious shortcomings which require improvement.